Field of the Invention
Embodiments of the present invention generally relate to a modular liner assembly utilized in a deposition chamber for semiconductor fabrication processes.
Description of the Related Art
Epitaxial growth of silicon-containing films has become increasingly important due to new applications for advanced logic and DRAM devices, among other devices. A key requirement for these applications is a lower temperature/low pressure process so that device features will not be damaged during fabrication of the device. Selective and blanket (e.g., non-selectively grown) epitaxial films containing silicon, and strained embodiments of such epitaxial films, which are grown at temperatures of a maximum of about 900 degrees C. to less than about 700 degrees C., are required for many current semiconductor applications. This lower temperature processing is not only important to forming a properly functioning device, but it minimizes or prevents the relaxation of metastable strain layers, helps to prevent or minimize dopant diffusion, and helps to minimize segregation of dopant within the epitaxial film structure. Suppression of facet formation and short channel effects, which is enabled by low temperature processing (i.e., low thermal budget processing), is a significant factor for obtaining high performance devices.
In a typical LPCVD process to deposit an epitaxial layer on a substrate, precursors are injected into a processing region in a chamber by a gas distribution assembly, and the precursors are energized above the surface of a substrate in the chamber by irradiation of the precursors in the processing region, which is typically low wavelength radiation, such as in the ultraviolet and/or infrared spectrum. Plasma generation may also be used to dissociate the reactants. To enable a more efficient precursor dissociation process, it is desirable to preheat the precursors prior to delivery to the processing region to enable faster and more efficient dissociation of the precursors above the substrate. However, the chamber body surrounding the processing region and the precursor inject region is fabricated from a metallic material such as stainless steel, and some of the precursors utilized in the LPCVD processes are reactive with these metallic materials. Thus, these metallic materials are potential sources for contamination that could damage chamber components as well as produce particulate contamination on the substrate.
To prevent unwanted reactions with the chamber body, liners have been utilized to shield some of the metallic chamber components from the processing region. However, the conventional liners are expensive to produce and replacement is difficult and time-consuming. Further, the conventional liners fail to perform satisfactorily with newer prescribed allowable contamination levels. Additionally, the conventional liners are used for shielding chamber components and are not typically utilized to provide different precursor inject and/or exhaust schemes. Further, the conventional liners are not modular components that facilitate ease of replacement of one or more liners for use with existing liners. In some cases, replacement of one conventional liner component requires fabrication of entirely new liner components. All of these factors may contribute to device contamination and/or cause significant chamber downtime, which increase cost of ownership of the tool and the devices produced therein.
Therefore, there is a need for an apparatus and method for a liner assembly that may be easily replaced and configured for different processes without significant downtime of the chamber, thus reducing cost of ownership.